Mig Welder Connection Identification

[jimybud]

Could someone please identify the below connection. The diameter is 5/8 inch or .625 inches. Sorry for the inch measurement; i am from the US.

 

[shenion]

That is a Tweco connection. Here one on my Tweco #4 gun (I have or had 4 Tweco guns):

It is 5/8" diameter. Most older machines use a Tweco connection (guns #1 through #4 use the same connection.)

Lincoln does one that is almost identical.